Kubernetes 1.29: Single Pod Access Mode for PersistentVolumes Graduates to Stable
Author: Chris Henzie (Google)
With the release of Kubernetes v1.29, the
ReadWriteOncePod volume access mode
has graduated to general availability: it's part of Kubernetes' stable API. In
this blog post, I'll take a closer look at this access mode and what it does.
ReadWriteOncePod is an access mode for
and PersistentVolumeClaims (PVCs)
introduced in Kubernetes v1.22. This access mode enables you to restrict volume
access to a single pod in the cluster, ensuring that only one pod can write to
the volume at a time. This can be particularly useful for stateful workloads
that require single-writer access to storage.
For more context on access modes and how
ReadWriteOncePod works read
What are access modes and why are they important?
in the Introducing Single Pod Access Mode for PersistentVolumes article from 2021.
How can I start using
ReadWriteOncePod volume access mode is available by default in Kubernetes
versions v1.27 and beyond. In Kubernetes v1.29 and later, the Kubernetes API
always recognizes this access mode.
To start using
ReadWriteOncePod, you need to create a PVC with the
ReadWriteOncePod access mode:
- ReadWriteOncePod # Allows only a single pod to access single-writer-only.
If your storage plugin supports
Dynamic provisioning, then
new PersistentVolumes will be created with the
ReadWriteOncePod access mode
Read Migrating existing PersistentVolumes
for details on migrating existing volumes to use
How can I learn more?
How do I get involved?
Special thanks to the following people whose thoughtful reviews and feedback helped shape this feature:
- Abdullah Gharaibeh (ahg-g)
- Aldo Culquicondor (alculquicondor)
- Antonio Ojea (aojea)
- David Eads (deads2k)
- Jan Šafránek (jsafrane)
- Joe Betz (jpbetz)
- Kante Yin (kerthcet)
- Michelle Au (msau42)
- Tim Bannister (sftim)
- Xing Yang (xing-yang)
If you’re interested in getting involved with the design and development of CSI or any part of the Kubernetes storage system, join the Kubernetes Storage Special Interest Group (SIG). We’re rapidly growing and always welcome new contributors.